| PublishDate | 2018-01 | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Positive_XBRL_Value | Enter a positive XBRL value for expense. | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Negative_XBRL_Value | Enter a negative XBRL value for reversal of expense. | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Note | If element is not presented separately in statement in which net income is reported, element identified in tin-part:AlternateElement is used to convey location within statement in which net income is reported. | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| PublishDate | 2018-01 | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| AlternateElement | DefinedBenefitPlanNetPeriodicBenefitCostCreditExcludingServiceCostStatementOfIncomeOrComprehensiveIncomeExtensibleList | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| SourceName | Improving Net Periodic Benefit Cost | http://fasb.org/srt/role/changeNote/changeNote |
| TaxonomyVersion | 2018 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2017-03 | http://fasb.org/srt/role/changeNote/changeNote |
| NewElement | true | http://fasb.org/srt/role/changeNote/changeNote |
| Source_ASU_Number | 2017-07 | http://fasb.org/srt/role/changeNote/changeNote |
| Publisher | FASB | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2003/role/disclosureRef |
| Topic | 715 | http://www.xbrl.org/2003/role/disclosureRef |
| SubTopic | 20 | http://www.xbrl.org/2003/role/disclosureRef |
| Section | 45 | http://www.xbrl.org/2003/role/disclosureRef |
| Paragraph | 3A | http://www.xbrl.org/2003/role/disclosureRef |
| Subparagraph | (b) | http://www.xbrl.org/2003/role/disclosureRef |
| URI | http://asc.fasb.org/extlink&oid=109237824&loc=SL108413299-114919 | http://www.xbrl.org/2003/role/disclosureRef |